District Attorney-elect Seth Williams says he plans to thoroughly shake up how crime is prosecuted in Philadelphia, with the goal of cracking down on the city's most violent and gun-prone criminals.

In a wide-ranging interview last week, Williams said he was "saddened as a Philadelphian" by an Inquirer investigative series reporting that the city had the highest violent-crime rate among big cities - and the nation's lowest felony conviction rate.

The series found the District Attorney's Office was winning a felony conviction in only one in five cases, less than half the national average.

"Unquestionably, we have to do a much better job," Williams said.

He said the newspaper's reporting this month "vindicated and validated what I've been saying for the last five years."

Williams, an assistant district attorney for 10 years who ran unsuccessfully for the top job in 2005, has been a longtime critic of District Attorney Lynne M. Abraham.

He has cited a federal study of conviction rates in 39 large urban counties that ranked Philadelphia last in two consecutive reports. The Inquirer series went beyond that study in an analysis of 31,000 criminal cases from 2006 to 2008, finding that Philadelphia defendants walk free on all charges in nearly two-thirds of violent-crime cases.

Williams detailed a series of changes that he predicted would distinguish his leadership from Abraham's. Referring to the city's low conviction rate, he said: "If that's the best you can do, then step aside. I'm glad I got the job. My administration won't be Lynne Abraham-lite."

Abraham, who will step down next month after 18 years in office, has rejected The Inquirer's statistical analysis and said that "you can't do justice by the numbers."

Any prosecutor, she said in a recent interview, could boost conviction rates by refusing to take on difficult cases or giving criminals sweetheart deals in return for guilty pleas.

Abraham said her philosophy has always been that every case is vitally important to the victim - and her staff.

Williams, 42, a Democrat, will take office Jan. 4 as the first African American ever to hold the post.

He said he would:

Appoint a new top deputy of policy, planning, and performance whose duties would include making public an annual statistical report on conviction rates.

Abraham has kept no such figures, eschewing a "justice-by-the-numbers" approach.

"They can't say what the numbers are," Williams said of Abraham and her staff. "They just say that they don't like them. That's no argument."

Williams acknowledged that "justice can't be quantified," but said there has to be some way to gauge the office's success and failure.

"If we're going to fix what's going on, we have to use some kind of empirical data," he said. "We have to begin measuring performance."

Overhaul the office's critical Charging Unit, putting experienced trial attorneys in place to kick cases back to detectives if evidence seems weak or flatly refuse to pursue cases if they seem unwinnable.

"The goal is to charge people with crimes that we believe we can convict beyond a reasonable doubt," Williams said. "It's not my responsibility . . . to say, 'We'll just see who shows up in court.' "

Push Philadelphia judges to streamline preliminary hearings in Municipal Court, permitting prosecutors to put on fewer witnesses in order to get a case held for trial in the higher Common Pleas Court.

In The Inquirer series, the paper disclosed that of cases that end without a conviction, 82 percent collapse in Municipal Court. Williams said that all too often judges insist that an array of witnesses show up for such hearings - victims, eyewitnesses, and multiple police officers, among others. The city's judges have for years held that this extensive evidence is needed to establish a prima facie case against a defendant, even though their counterparts in the rest of the state do not impose such stringent requirements.

"In the entire state, only Philadelphia puts on these mini-trials for preliminary hearings," Williams said. "You don't need all these witnesses for every hearing."

Speed up the office's review of cases of police misconduct and shootings.

In some controversial police shootings, the investigations have "dangled in limbo" for years, Williams said.

The slow process also can drag out police disciplinary reviews, because Internal Affairs is barred from speaking to officers until the D.A.'s Office clears them of any criminal wrongdoing.

Williams said he had talked to Police Commissioner Charles H. Ramsey, Mayor Nutter, and their deputies, as well as to the police union. All have asked for the office to move more quickly on these cases.

Establish an internal Capital Case Review Committee to oversee the office's decisions about when to seek the death penalty in homicide cases.

Williams said this policy shift likely would mean the office would pursue the death penalty in fewer cases.

Critics who dubbed Abraham "America's deadliest D.A." accused her of frequently seeking the death penalty to gain an advantage in murder cases. Because jurors opposed to capital punishment are weeded out, panels in death-penalty cases tend to be more conservative.

"My overall philosophy is that we have to use the death penalty more judiciously, not just as a bargaining chip," Williams said.

Quickly dispense with low-level offenses such as property crimes and minor drug charges. Defendants could be offered diversion programs or flat sentences, which can be shorter but have no parole eligibility. Flat sentences spare defendants and court personnel long periods of supervision.

"If we handle this stuff better . . . we can use our resources on violent crime," he said.

Many of the changes Williams discussed have a similar purpose - to unclog the criminal justice system and free up prosecutors to focus on the violent felons who, Williams said, commit a disproportionate amount of the crime.

"As a proposition, as a direction he wants to go in, it's unassailable," said Mark Aronchick, a prominent lawyer and former city solicitor. "It's the correct thing."

Aronchick and JoAnne Epps, dean of Temple University's law school, have been cochairing a transition committee of roughly 100 participants that has been broken into about a dozen subcommittees.

"He isolated on the Charging Unit and he isolated on the preliminary hearings because that's the up-front stuff," Aronchick said. "That's the stuff that clogs the system."

Whether Williams can unilaterally change the long-standing practices of preliminary hearings remains to be seen.

"These are very interesting issues he'll have to confront," Epps said. "There is a lot of tradition in the city. Judges will have to change their expectations."

Epps also applauded Williams' effort to collect empirical data, but said he would have to do so "in ways that prove useful."

"I do think he has a challenge of what to count, and how to count it," she said.

Williams acknowledged that with the changes he proposes, particularly dispensing with bad cases at the charging level, he opens himself up to the criticism that he takes on only winnable cases.

"I'm not saying we're going to give you a pass if you shoot somebody," he said. "I'm saying let's use our resources better."

While Williams said driving up the conviction rate, especially for violent offenders, is crucial, he returned throughout the interview to the idea that his job is to make the city safer.

He talked admiringly of the Brooklyn District Attorney's Office, which has an entire unit dedicated to crime prevention.

"Your family would prefer that you were not shot, not that you were shot and, damn it, the D.A.'s Office handled it well," he said. "There has to be new ways to figure out what it means to be a D.A."

Referring to a "holistic approach," Williams discussed the nontraditional ways he could attack crime, such as reaching out to community groups and schools.

Epps said Williams had brought a number of people, such as victims' advocates and anti-gun-violence groups, who are not "obvious allies to the D.A.'s Office," into the transition process.

Williams said that illegal guns would be a focus of his administration, and that he would lobby to add to state law a Philadelphia-only mandatory sentence for possession of an illegal firearm.

The law would be similar to one in New York City, used to send former New York Giants football player Plaxico Burress to prison for carrying a gun illegally.

"He wants to be a significant voice on decreasing gun violence," Aronchick said. "He's also a public official with a big voice, and lobbying for change is something he feels strongly about."

As Williams talked, he sat behind a neatly organized desk that bore a management advice book, The First 90 Days, written by a former Harvard University professor. He was clearly already grappling with the budgetary headaches he is soon to inherit.

The D.A.'s Office is now operating under a $29 million budget, a deep 9 percent cut from the previous fiscal year.

Williams said Nutter's budget staff had already warned that the administration was seeking a further 7.5 percent reduction in the office's funding in the next fiscal year, which will start July 1.

"I can't spend money like a drunken sailor, but I don't think we can stand a reduction, let alone 7.5 percent," he said.

As district attorney, Williams will oversee 318 assistant district attorneys who have gone two years without a pay raise. The office also has 175 support personnel, far fewer than in similar offices around the nation.

The staff keeps shrinking, he said.

In a city with a widespread problem with witness intimidation, Williams noted, the office has only 23 victim/witness service staffers, eight fewer than on the payroll at the start of 2009.

Williams said that at times, people working in the D.A.'s Office "in many ways feel like they're on a Bataan death march in a system built for failure."